There has been a demand for eliminating the use of batteries from remote controllers used for television sets, air conditioners, lighting apparatuses, and the like. The use of batteries have various problems. Dry-cell batteries are consumables and eventually used up. Users therefore bother to set new batteries. In addition, batteries result in industrial wastes with a high disposal cost.
In order to meet the above demand, practical use of a “power generation switch”, which is capable of generating power by receiving an action (mechanical action) of pressing a button by a human and transmitting signals generated by the power to a television set, an air conditioner, a lighting apparatus, and the like, has been examined. If such switches can be used practically, remote controllers do not need batteries, for example. In addition, for example, wiring in walls to set up switches in home is not necessary, and therefore the switches can be arranged at any desired places.
Conventionally, as principles of generating power by a linear motion of a human finger, (A) a principle using an electrical magnet and (B) a principle using a piezoelectric material have been known.
For example, Non-Patent Literature 1 is known as the technique using an electrical magnet. A power generation switch disclosed in Non-Patent Literature 1 includes an electrical magnet (combination of a coil, a fixed yoke, a movable yoke, and a magnet) and a projection fitting. A user causes the projection fitting to execute linear motion with respect to the electrical magnet. As a result, the movable yoke becomes movable according to the motion of the projection fitting, and power is generated by temporal changes of interlinkage magnetic flux of the coil according to the motion of the movable yoke.
On the other hand, an example of the technique using a piezoelectric material is disclosed in Patent Literature 1. As shown in FIG. 18, in a power generation switch disclosed in Patent Literature 1, a piezoelectric element 1a having a plate shape is bonded with a leaf spring (supporting plate) 1b, and the leaf spring 1b is oscillated to induce an electromotive force in the piezoelectric element 1a. 